As demand for higher speed and higher density integrated circuit devices grows, signal and power integrity have become increasingly crucial in the design of high-speed integrated circuits. As such, the application of a multi-layer substrate becomes an important component for the manufacturing of integrated circuits. Generally, a multi-layer substrate may include stacked metal layers on which printed circuit patterns are formed and insulating layers formed between the metal layers. Depending on design requirements, via holes or vias may be formed in the substrate to make electrical connections between the metal layers.
In general, the capacitive behavior of vias reduces the characteristic impedance of the vias. Subsequently, a significant impedance mismatch or discontinuity may occur between the vias and the substrate, as signal frequency increases. An impedance mismatch creates reflections that may corrupt the integrity of the signal data stream, which increases jitter and degrades signal quality.